Magnetic resonance imaging follow-up of chondroid tumors: regression vs. progression

To present magnetic resonance imaging (MRI) evidence of the regression or progression of chondroid tumors and to investigate whether MRI can be used to predict the evolution of chondroid tumors.

Twenty-one patients with enchondromas or atypical cartilaginous tumors who had undergone extremity MRI at least twice with a minimum 12-month interval between the MRIs were enrolled in this study. The diagnosis was based on the radiography and MRI findings. We classified the tumors into the following three groups according to changes between the MRIs: no change (NC), progression (P), and regression (R). We assessed the initial MRI features, including anatomical location, size, endosteal scalloping, peritumoral edema, fat entrapment, and direction of progression or regression. Nineteen of the 21 patients had contrast-enhanced images, and we analyzed the presence of atypical lobular enhancement against typical peripheral or septal enhancement.

The R group comprised 11 cases (52%), the P group comprised five cases (24%), and the NC group comprised five cases (24%). None of the MRI features showed statistically significant differences among the groups. Atypical lobular enhancement was observed in the R (6 of 10, 60%) and NC (2 of 5, 40%) groups but not in the P group (0 of 4, 0%), although these differences were not statistically significant.

Chondroid tumors can either regress or progress in the MRI follow-up. Atypical lobular enhancement was seen only in stable or regressing tumors.